The use of digital signals for television broadcasts and the transmission of other types of video and audio signals allow a significant improvement in picture quality and a more efficient use of bandwidth over that currently possible using analog television signals. The Advanced Television Systems Committee (ATSC) is a standards organization that was created to promote the establishment of technical standards for all aspects of advanced television systems. The ATSC adopted 8-VSB (vestigial sideband) standard radio frequency modulation format for the broadcast of digital TV signals, because of its large bandwidth, which is needed to transmit HDTV programming. With this carrier modulation type, the modulating data appears in the form of signal components at frequencies slightly higher and lower than that of the carrier; these components are called sidebands. As the lower sideband (LSB) and the upper sideband (USB) are essentially mirror images of each other, one can be discarded or used for a second channel (also referred to as a secondary channel), or for diagnostic purposes.
In recent years, the customer premise equipment has evolved to enable the user with additional services that become more sophisticated as new features are envisaged. Currently, users of multimedia entertainment content can interact with the server that provides the content using a device generally called a “set-top box” (STB). Among the most useful and important features of modern STBs are channel browsing or surfing, visual bookmark capability, the capability of simultaneous viewing of more than one channel, etc.; new features emerge based on user demands. While some viewers may use a program guide for this purpose, others may wish to see what programs are currently playing as opposed to reading about these only. Still further, some users may wish to view two or more programs simultaneously.
All of these features can be provided by showing reduced-size versions of the channels content concurrently in one or more small areas of a display screen. This capability is known as picture-in-picture (PIP). For example, a reduced-size image of a program playing on another channel may be displayed on the user's screen as a part of a video browsing function, while the currently selected content continues playing.
Various technologies are available for “summarizing” or “previewing” different types of media content. For example, technology is available for removing pauses from spoken audio content. Audio content can also be summarized with algorithms that detect “important” parts of the content as identified by pitch emphasis. Similar schemes can be used with other types of media streams, such as video streams, animation streams and script streams. For example, the MPEG (Moving Picture Experts Group) standard defines how the video data should be encoded (summarized), decoded and streamed to the clients for playback.
Picture in Picture is a common staple in video, frequently used in TV news shows, and is also applicable to most security systems that need to visually survey a plurality of points of interest. Picture in Picture can also be used on a player for the purposes of watching a recording while using the secondary frame to show the viewer what other desired broadcast programming is on.
PIP allows one to watch more than one TV program (channel) at the same time on television sets or other devices. With PIP feature, one program will be displayed on the entire TV screen, and another program or programs will be displayed in individual smaller squares on the screen. Picture in Picture requires today two independent tuners one supplying the large picture and the other, the small picture. Single tuner PIP TVs require the use of the DVD/VCR tuner to act as the second tuner, while two-tuner PIP TVs have a second tuner built in for this purpose. Some users find that using the DVD/VCR as the second tuner can be difficult to hook-up and confusing to use.
Picture-in-picture images can be created using one or more passes, and the smaller image can be placed anywhere in the frame, presented in the original shape or as a circle, and have hard or soft edges.
It is also desirable to have multiple reduced-size images (thumbnail images) shown concomitantly on the screen. These reduced size images may be derived from stored video streams (e.g., stored in memory or on a disk drive), video streams being recorded or obtained “on-the-fly” in real time from a video stream being displayed.
However, due to the high computational overhead associated with the derivation of reduced-size images, dedicated decoding hardware is also employed for these features, often requiring completely separate decoding hardware for the reduced-size image production. As a result, the current systems either require complex video multiplexing or transcoding systems to process client requests for picture-in-picture views, or require the client to receive and decode two or more full video streams to preview additional channels. Hence, in the case of the former solution, they are too costly, and in the case of the latter solution, they are too resource intensive within the client-side equipment.
There is a need for viewing multiple channels at once. Not only would such a solution alleviate the aggravation of the channel surfing, it would also allow the channel surfers to minimize their practice. Ideally, such a solution should require minimal changes to the existing digital multimedia systems equipment. Also, such a solution should be usable on most, if not all existing digital multimedia systems.
Therefore there is also a need to provide a cost-effective and resource efficient technique to provide advanced picture-in-picture support. For example, there is a need for a method and apparatus able to implement picture-in-picture capability in a digital multimedia system, without incurring the cost of multiple full resolution decoders.